This program project brings together a dynamic team of experienced HIV investigators who bring individual and collective strengths to design and test novel vaccines to elicit neutralizing antibodies (NAbs). The overall goal is to design novel vaccines based on env genes from HIV-infected subjects who develop broad NAbs in an accelerated fashion. In Project 1 (L Stamatatos), we will identify multiple HIV-1 infected, ART-naive subjects who developed both autologous and broad cross-neutralizing Abs within the first 2-3 years of infection and characterize the epitope-specificities of these NAbs. With Project 3, we will define changes that accrue to the subjects'cloned quasispecies Envs from initial infection through broadening. We hypothesize that specific diversification of the quasispecies drives maturation of broad cross NAbs in vivo, by presenting new epitopes in escape variants, or by focusing the response on more conserved epitopes. In Project 2 (S Kalams), we will characterize the temporal development and maintenance of functional T-helper (Th) responses that allow B cells to respond to the changes in the Env proteins produced by the patient's quasispecies variants in Project 1. We hypothesize that the initial ability to generate NAbs correlates with a relatively intact CD4+ Th response early in infection, ultimately lost with continued viremia. We will adapt a novel technology to sort Env-specific B cells from these subjects and characterize NAbs that neutralize diverse isolates, to refine our choice of Env immunogens. In Project 3 (N Haigwood), we will work with Project 1 to clone env gp160 variants to define the autologous NAbs and the pathways of env escape;vaccines will be based on these natural longitudinal env variants that arise during broadening. Variants will be used singly and in mixtures to "program" humoral immunity in vaccinated rabbits and macaques. We hypothesize that the responses in vivo will result in broader NAbs than those elicited by other vaccine strategies. The Program is supported by Core A (Stamatatos) to develop protein immunogens, by Core B (L Picker and M Axthelm) to provide expertise in nonhuman primates and T cell analyses in macaques, and Core C (Haigwood) to support the entire Program with administrative support and biostatistics. PROJECT 1: Longitudinal analysis of development of broad HIV-1 neutralizing antibodies (Stamatatos, L) PROJECT 1 DESCRIPTION (provided by applicant): The overall goal of our grant proposal is to evaluate the possibility that natural HIV viral env sequences that emerge during the course of HIV infection, can be used as immunogens to elicit broadly-reactive anti-HIV neutralizing antibodies. These env sequences will be derived from HIV infected subjects which during a very short period of time (2-3 years) developed broad and potent anti-HIV cross-neutralizing antibody responses. In Project 1, we will monitor HIV infected subjects to identify those that develop broad cross-neutralizing antibody responses shortly following infection and we will characterize in detail these responses. We will amplify viral env from longitudinal samples from these patients and in conjunction with Project 2 we will examine what role the CD4+ T cell helper responses have in the development and maintenance of broad anti-HIV neutralizing antibody responses. The Envs identified in this Project 1 will be used as immunogens in Project 3 to test the hypothesis that they can elicit broad cross-neutralizing antibody responses in animals.